An atypical concentration or presence of substances in body fluids or in body lumens may be indicative of the biological condition of the body. For example, the presence of elevated concentrations of red blood cells in the gastrointestinal (GI) tract may indicate different pathologies, depending on the location of the bleeding along the GI tract. Early detection, identification and location of abnormal conditions may be critical for correctly diagnosing and treating various pathologies.
In some cases diseases, such as, for example, cancer may be detected by analyzing the blood stream for tumor specific markers, for example, specific antibodies. One of the drawbacks of this method is that the appearance of antibodies in the blood stream may usually occur at a late stage of the disease, such that early detection may not be possible.
Detection of some pathologies in the GI tract may be performed using an endoscope; however, such detection may be limited to the upper or lower gastrointestinal tract. Thus, pathologies in other parts of the GI tract, such as, for example, the small intestine, may not be easily detected by endoscopy.
In vitro testing of body fluid samples for the presence of a suspected substance may be performed. For example, immunoassays may be used for the determination, either qualitative or quantitative, of some substances, such as, for example, peptides, proteins, enzymes, hormones, vitamins, drugs, carbohydrates, or the like, in a sample. In a typical immunoassay, to detect the presence, or measure the concentration, of an analyte or marker of interest, especially in a liquid sample, the analyte has to be separated from the rest of the proteins in the sample. This is typically performed by specifically binding the analyte to a binding component for the analyte, followed by a separation process that extracts the bonded species from the rest of the sample. As the bonding reaction might be slow, the sample and the binding component for the marker (analyte) are usually incubated for a sufficient time to allow a marker contained in the sample to bind to the binding component. A typical example of such a binding component may be a marker-specific antibody, e.g., a monoclonal antibody with specificity for the marker in question. However, other kinds of substances and structures may also qualify as a binding component.
Typically these in vitro methods of detection are carried out in a lab using cumbersome and complicated machines. Complicated machines may be needed, for example, because of the complicated requirements of such procedures which may involve multiple reactions and/or different conditions for each reaction, and typically washing in between reactions. Furthermore, these methods of detection, when carried out in vitro, may not easily enable the localization or identification of the origin of an abnormally occurring substance.
In many instances, locating an abnormally occurring substance in a body lumen may greatly contribute to the identification of pathology, and thus may contribute to the facile treatment of the identified pathology.